Nosema
Nosema apis, a microscopic fungus that affects honeybee colonies. It is very serious, causing losses in autumn and spring. It can be treated with antibiotic – fumagillin – obtained from a veterinarian.
Signs of a nosema infection are dysentery at hive entrances or inside the hive. Bees are very hygienic. They do not opt to “use the restroom” inside their home. This shows they are ill. K-wing, lethargy, and greasy looking bees are indicators. Reduced egg laying and poor Spring build-up with reduced population are bad signs. The only true way to diagnose is a microscopic check performed by a specialist.
Sacbrood Virus [SBV]
Sacbrood virus often affects worker larvae, but may also affect adult bees. Highly infectious, this virus will result in honey production losses. Symptoms are observed as bees remove dead larvae from their nest. Pinholes may be present on sunken pupa. There is no odor.
Prevention and treatment involves maintaining clean equipment, healthy, strong colonies, and caution when buying or trading materials. Antibiotics do not resolve SBV. Varroa mite doesn’t exactly cause SBV, but they can be carriers. Contaminated food may also be a transmission point. Maintaining low levels of varroa is the best way to keep strong colony health.
Chalkbrood
Chalkbrood is another highly contagious fungal disease in the larvae. It is observed as larvae turns into hard, white, or even black “mummies”. It spreads on contaminated equipment, tools, and food. It’s more likely to affect a weak or chilled colony. It may be spread by drifting worker bees.
Prevention of chalkbrood is in maintaining strong, dry, well-ventilated hives.